package com.heima.schedule.service.impl;

import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.heima.common.constants.ScheduleConstants;
import com.heima.common.redis.CacheService;
import com.heima.model.schedule.dtos.Task;
import com.heima.model.schedule.pojos.Taskinfo;
import com.heima.model.schedule.pojos.TaskinfoLogs;
import com.heima.schedule.mapper.TaskinfoLogsMapper;
import com.heima.schedule.mapper.TaskinfoMapper;
import com.heima.schedule.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Set;

@Service
@Transactional
@Slf4j
public class TaskServiceImpl implements TaskService {
    /**
     * 添加延迟任务
     * @param task
     * @return
     */
    @Override
    public long addTask(Task task) {
        //1,添加任务到数据库中
        boolean success=addTaskToDb(task);
        if(success){
            //2，添加任务到redis中
            addTaskToCache(task);
        }


        return task.getTaskId();
    }

    @Autowired
    private CacheService cacheService;

    private void addTaskToCache(Task task) {
        String key=task.getTaskType()+"_"+task.getPriority();

        //获取未来5分钟之后的时间 毫秒值
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MINUTE,5);
        long nextScheduleTime = calendar.getTimeInMillis();

        //2.1如果任务的执行时间大于当前时间，存入list
        if(task.getExecuteTime()<=System.currentTimeMillis()){
            cacheService.lLeftPush(ScheduleConstants.TOPIC+key, JSON.toJSONString(task));
        }
        else if(task.getExecuteTime()<=nextScheduleTime){
            //2.2 如果任务的执行时间大于当前时间&& 小于等于预设时间（未来5分钟）存入zset中
            cacheService.zAdd(ScheduleConstants.FUTURE+key,JSON.toJSONString(task),task.getExecuteTime());
        }

    }

    @Autowired
    private TaskinfoMapper taskinfoMapper;
    @Autowired
    private TaskinfoLogsMapper taskinfoLogsMapper;

    /**
     * 添加任务到数据库中
     * @param task
     * @return
     */
    private boolean addTaskToDb(Task task) {
        boolean flag=false;
        try {
            //保存任务表
            Taskinfo taskinfo = new Taskinfo();
            BeanUtils.copyProperties(task,taskinfo);
            taskinfo.setExecuteTime(new Date(task.getExecuteTime()));
            taskinfoMapper.insert(taskinfo);

            //设置taskID
            task.setTaskId(taskinfo.getTaskId());

            //保存任务日志数据

            TaskinfoLogs taskinfoLogs = new TaskinfoLogs();
            BeanUtils.copyProperties(taskinfo,taskinfoLogs);
            taskinfoLogs.setVersion(1);
            taskinfoLogs.setStatus(ScheduleConstants.SCHEDULED);
            taskinfoLogsMapper.insert(taskinfoLogs);
            flag=true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }

    /**
     * 取消任务
     * @param taskId
     * @return
     */
    @Override
    public boolean cancelTask(long taskId) {
        boolean flag=false;
        //删除任务，更新任务日志
        Task task=updateDb(taskId,ScheduleConstants.CANCELLED);

        //删除redis的数据
        if(task!=null){
            removeTaskFromCache(task);
            flag=true;
        }

        return flag;
    }

    /**
     * 删除redis中的数据
     * @param task
     */
    private void removeTaskFromCache(Task task) {
        String key = task.getTaskType() + "_"+task.getPriority();
        if(task.getExecuteTime()<System.currentTimeMillis()) {
            cacheService.lRemove(ScheduleConstants.TOPIC + key, 0, JSON.toJSONString(task));
        }
        else {
            cacheService.zRemove(ScheduleConstants.FUTURE + key, JSON.toJSONString(task));
        }

    }

    /**
     * 删除任务，更新任务日志
     * @param taskId
     * @param cancelled
     * @return
     */
    private Task updateDb(long taskId, int status) {
        Task task = null;
        try {
            //删除任务
            taskinfoMapper.deleteById(taskId);

            //更新任务日志
            TaskinfoLogs taskinfoLogs = taskinfoLogsMapper.selectById(taskId);
            taskinfoLogs.setStatus(status);
            taskinfoLogsMapper.updateById(taskinfoLogs);

            task = new Task();
            BeanUtils.copyProperties(taskinfoLogs, task);
            task.setExecuteTime(taskinfoLogs.getExecuteTime().getTime());
        } catch (Exception e) {
            log.error("task cancel exception taskId={}", taskId);
        }
        return task;
    }

    /**
     * 按照类型和优先级拉取任务
     * @return
     */
    @Override
    public Task pull(int type,int priority) {
        Task task=null;
        try{
            String key = type + "_" + priority;

            //从redis中拉取数据 pop
            String task_json = cacheService.lRightPop(ScheduleConstants.TOPIC+key);
            if(StringUtils.isNotBlank(task_json)){
                task = JSON.parseObject(task_json, Task.class);

                //修改数据库信息
                updateDb(task.getTaskId(), ScheduleConstants.EXECUTED);
            }
        }catch (Exception e){
            e.printStackTrace();;
            log.error("pull task exception");
        }
        return task;
    }

    /**
     * 未来数据定时刷新
     */
    @Scheduled(cron = "0 */1 * * * ?")
    public void refresh(){

        String token = cacheService.tryLock("FUTURE_TASK_SYNC", 1000 * 30); //redis的分布式锁解决多线程抢占任务
        if(StringUtils.isNotBlank(token)){
            log.info("未来数据定时刷新---定时任务");

            //获取所有未来数据的key
            Set<String> futureKeys = cacheService.scan(ScheduleConstants.FUTURE + "*");
            for (String futureKey : futureKeys) {//future_100_50

                //获取当前数据的key topic
                String topicKey = ScheduleConstants.TOPIC + futureKey.split(ScheduleConstants.FUTURE)[1];

                //按照key和分值查询符合条件的数据
                Set<String> tasks = cacheService.zRangeByScore(futureKey, 0, System.currentTimeMillis());

                //同步数据
                if(!tasks.isEmpty()){
                    cacheService.refreshWithPipeline(futureKey,topicKey,tasks);
                    log.info("成功的将"+futureKey+"刷新到了"+topicKey);
                }
            }
        }

    }

    /**
     * 数据库任务定时同步到redis
     */
    @PostConstruct
    @Scheduled(cron = "0 */5 * * * ?")
    public void reloadData(){
        // 清理缓存（redis) 中的数据 list zset
        clearCache();

        //查询符合条件的任务 小于未来5分钟的数据
        //获取5分钟之后的时间 毫秒值
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MINUTE,5);
        List<Taskinfo> taskinfoList = taskinfoMapper.selectList(Wrappers.<Taskinfo>lambdaQuery().lt(Taskinfo::getExecuteTime, calendar.getTime()));

        //把任务添加到redis
        if(taskinfoList!=null&& taskinfoList.size()>0){
            for (Taskinfo taskinfo : taskinfoList) {
                Task task = new Task();
                BeanUtils.copyProperties(taskinfo,task);
                task.setExecuteTime(taskinfo.getExecuteTime().getTime());
                addTaskToCache(task);
            }
        }
        log.info("数据库任务同步到了redis");
    }

    /**
     * 清理缓存中数据
     */
    private void clearCache() {
        Set<String> topicKeys = cacheService.scan(ScheduleConstants.TOPIC + "*");
        Set<String> futureKeys = cacheService.scan(ScheduleConstants.FUTURE + "*");
        cacheService.delete(topicKeys);
        cacheService.delete(futureKeys);

    }
}
